Migraine Term of the Day - Cortical Spreading Depression

Writer's note: Some of you have expressed an interest in learning more of the medical terminology that comes up when discussing migraine disease and other headache disorders. So, I'll be posting a "term of the day," on a regular basis. If there are terms you'd like to have defined, please leave a comment below.

When we're given migraine and headache information, whether from our doctor, a book, or an online article, we sometimes come across medical terms that can be confusing. While it's easy enough to substitute another word or a short phrase for the medical term, there are times when substituting doesn't quite convey the same meaning.

Cortical spreading depression (CSD), is one of those terms. It's frequently used when talking about migraine symptoms and medications and is also an important word for migraineurs to understand.

Definition:

Cortical spreading depression is a wave of abnormal electrical activity that sweeps the brain when a migraine trigger is encountered.

Here's an example of how it's used in a sentence:** Cortical spreading depression** starts a chain of reactions in the brain that cause the various symptoms of a migraine attack.

Discussion:

For many years, migraine was thought to be vascular — that the first pathophysiological response when someone with migraine disease encountered a trigger, was their cerebral blood vessels constricting for a fraction of a second, then dilating. It was theorized that these vascular changes caused the pain and other symptoms of a migraine attack. Later research showed the "vascular theory" to be inaccurate. The newer research showed:

Cortical spreading depression occurs before any vascular changes.

Vascular changes may or may not occur during a migraine and are not necessary for the pain and other symptoms to occur.